Research On Single Rotary Inverted Pendulum System Control Stratety

As a controllerd object,rotary inverted pendulum has typical features such as nonlinear, strong coupling, underactuated and open-loop unstable. As an experimental platform, rotary inverted pendulum has the advantages of simple equipment, easy to operate and obvious experimental effect. Therefore, more and more researchers regard the inverted pendulum system as a benchmark system to measure, test, evaluate and compare the effectiveness of different control algorithms. The control principle of the rotary inverted pendulum system has also been applied in various fields of aerospace, engineering, robotics, etc. The control research for the inverted pendulum system includes the swing-up control, stability control and tracking control. Aiming at the stability control and trajectory tracking problems of the rotary inverted pendulum system, dynamic model of the rotary inverted pendulum system was built and many control strategies were presented. The main works in this paper as follows:Firstly, based on the analysis of the system structure, the dynamics modeling was established by using Lagrange method. While considering the system state near zero, the linear model was obtained after the linear processing. While further considering the internal system uncertainties and external disturbances, the nonlinear dynamic model of the system was obtained.Secondly, for the linear model, a linear quadratic optimal controller(LQR) with self-adjusting part. The contoller could make the traditional LQR controller adjust the output based on the actual condition of the system statement. The simulation results show that the controller improved the dynamic performance and steady-state performance of the closed-loop system. Then the above controller was verified by rotaryl inverted pendulum experiment platform produced by Quanser company, the experiment results show that the LQR self-adjusting controller could succeed the implementation of the system’s stability control and trajectory tracking control.Thirdly, considering the output jitter phenomenon of the traditional sliding mode controller(SMC) caused by the design of the reaching law, a new sliding mode controller with variable gain reaching law was presented. The controller could not only weaken the jitter phenomenon but also retrain the advantages of the SMC for its appreciable features, such as design simplicity and robustness. The simulation results show that the design of variable gain sliding mode controller improves the dynamic characteristics of the system and weaken the system jitter phenomenon at the same time.Finally, the global dynamic fast terminal sliding mode control based on extended state(ESO), the ESO is used to estimate the external disturbance and internal parameter uncertainties in real-time and compensate the observed value to the control law. The global dynamic terminal sliding successfully solve the chattering problem of the conventional sliding mode controller, and further improve the stability and robustness of the system. Simulation results show the effectiveness and superiority of above controller.